1. Field of the Invention
The present invention relates to fastener strips or assemblies. More particularly, the present invention is directed to an apparatus and a method for producing assemblies of headed fasteners fixed in an aligned relationship.
2. Background of the Invention
With the advent of rapid action fastener driving tools, it has become desirable to reduce the loading time of the tools and to have an assembly of fasteners in either strip or coiled form to be used in the magazines of such tools. The shape of the fastener and also that of the assembly of fasteners may vary considerably. Each fastener of the assembly of fasteners typically has a driver striking end, a shank and a workpiece entering end. The workpiece entering end of each fastener may be formed as a round, diamond, chisel or blunt point. The shanks ar the elongated portions connecting the driver striking end to the workpiece entering end and are fixed in a parallel relationship to one another. The driver striking end of each fastener may be the same shape as the shank or may be deformed to provide a "headed" portion.
Customarily, the term "headed" is used to distinguish a fastener that has the driver striking end deformed from a fastener that does not have the driver striking end deformed and is commonly known as a "pin". The head of the fastener may be formed in various shapes, some of which are "T" shaped, offset, moon-shaped, half-round and full round. The full round head, normally, has a diameter at least twice that of the shank and is generally known as a "common nail". Although the odd-shaped heads allow the fasteners to be assembled with the shank portions adjacent and thereby provide more fasteners in a given space, the user ordinarily prefers the full round head nail for normal fastening applications because of the greater holding power. For example, when two pieces of material are fastened together they are kept from separating by the ability of the shank to grip the lower piece of material and of the head to resist being pulled through the upper piece of material. Because the full round heads have a larger surface area than that of the other common shapes, the holding power is greater with all other conditions being equal.
The normal method of assembling round head nails is to first manufacture the nail on a nail producing device and then store the nails produced in bins. The nails are then taken from the bins and placed in a track to align the shanks in a parallel relationship with all of the heads in the same direction. The aligned nails are then transferred from the track into a third device that separates the shanks to a predetermined, spaced-apart distance and then bonds them together with a collating material. The assembled strip of nails is then cut into desired lengths and either left in assembly form or wound into coils. The type of collating material utilized will determine if the assembly of nails can be wound into coils. A few types of materials used for collating are paper and glue, molded plastic, wire welded to shanks, preformed plastic bands, and perforated steel strips.
This method of assembly, or some variation thereof, provides an acceptable finished product but the cost and size of the equipment is considerable. Furthermore, if the time between the forming and collating of the nails requires the nails to be stored, they may have to be cleaned before collating to assure an adequate bond. This, of course, will add to both the cost of manufacture and the amount of space required in the manufacture of the fastener strip.
Another disadvantage of the heretofore known method of assembling fastener strips is of the possibility of intermixing nail sizes and lengths. To change from one size nail to another size nail, all of the nails in the system must be used or else the uncollated nails must be removed from the equipment. Although care is normally taken during the changeover or in the addition of nails to the system during the normal production of the strip of nails, inadvertently, some nails may become mixed. The intermixing of different size nails will result in a defective product or machine downtime to clear the odd size nails from the equipment.
Some fastening applications require that the size of the head of the nail is small when the holding power of the nail is not important. These applications include the finish trim around windows and doors as well as the use of other decorative types of materials. Since the head can be small, the most common type of fastener is one having a T-shaped head. This term identifies a head that is in one direction the same thickness as the shank, while larger in the opposite direction. The T-shaped head allows the shank portions to be collated adjacent one another by a different method than the previously described method used for the full round head nail.
A selected number of wires may typically be laid adjacent to one another and then bonded together by glue, or the like, to form a band or web of wires. Next, the web is cut into clips or assemblies of a desired fastener length or number of wires. The assemblies are then held tightly in a clamp-like device while a punch strikes the clip along one of the cut edges. The end of each wire deforms into a rectangular shape with the smaller dimension being the same size as the diameter of the wire. The finished product is a fairly rigid assembly of T-shaped nails also known as brads, such as that described in U.S. Pat. No. 3,095,588. Another method of producing the T-shaped head is to form the head on the end of the band first, and then cut the band to the desired length to form the assembly of brads. The brads produced by either method are then driven from a tool with a magazine adapted to accommodate such an assembly. One of the biggest disadvantages in this method of producing fasteners is the number of fasteners in the clip or assembly is limited to the number of wires to make the clip. Another disadvantage is that as the number of wires to be headed in a single stroke is increased, the size of the heading equipment becomes very large.
Another method of producing an assembly of T-shaped nails is to produce the nail first and then align the nails in a fashion identical to that described for the round head nails. Normally, this method is used for the larger T-shaped nails because the adjacent alignment of smaller sized heads is more difficult after the nail is formed. Therefore, for the smaller sized T-shaped nails formation of the head after the clip has been assembled is preferable.
An object of the present invention is to provide an improved method of producing an assembly of fasteners in a continuous process from at least one strand of wire.
Another object of the invention is to provide a method of forming a variety of different head types of the fastener after the shank portions have been aligned and bonded together to form an assembly of headed fasteners.
A further object of the present invention is to provide an assembly of fasteners arranged in an aligned fashion such that each shank is of a uniform length.
Still a further object of the present invention is to provide a method of forming an assembly of fasteners arranged in a spaced apart fashion such that the length of the individual fastener may be varied with minimum cost and loss of production time.